Vapor mitigation system, vapor mitigation controller and methods of controlling vapors

ABSTRACT

A vapor mitigation system includes at least one vacuum pipe configured to collect vapors beneath a floor of a building, and a blower coupled to the at least one vacuum pipe. The blower is configured to create a vacuum under the floor of the building. The vapor mitigation system includes a controller configured to control a speed of the blower. The controller adjusts the speed of the blower in response to a level of vacuum created under the floor of the building.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/529,864, filed on Jun. 21, 2012, which claimsthe benefit of U.S. Provisional Application No. 61/502,346, filed onJun. 29, 2011, and U.S. Provisional Application No. 61/499,672, filed onJun. 21, 2011, the contents of each application being incorporatedherein by reference in their entirety.

TECHNICAL FIELD

The present application generally relates to vapor mitigation systems,and more particularly, to dynamically controlled vapor mitigationsystems, vapor mitigation controllers and methods of controlling andmitigation vapors.

BACKGROUND

Vapor intrusion is a process by which chemicals (e.g., volatile organiccompounds (VOCs), methane, radon, ect . . . ) in soil and/or groundwatermitigate to or seep into building spaces. These vapors can be releasedfrom contaminated soil and/or groundwater underneath buildings, and mayenter basements, crawl spaces, rooms and/or other areas of a building orstructure. As a result of vapor intrusion, the air within buildings maybecome contaminated thereby exposing individuals within the buildings tochemical contamination, such as VOC and/or radon contamination.

Generally, VOCs are man-made chemical compounds that have a high vaporpressure and low water solubility. VOCs can be used and produced in themanufacture of fuels, paints, pharmaceuticals, and refrigerants, and aretypically included in industrial solvents, paint thinners,tetrachoroethene (dry cleaning fluid), fuel oxygenates (MTBE), andby-products produced by chlorination in water treatment. VOCcontaminants can travel with or on top of groundwater, and can easilybecome gaseous and migrate through soil. As a result of negativepressures that are induced by various building designs and features,VOCs can be drawn from the soil and/or groundwater, and into occupiedspaces of buildings where human exposure can occur.

Radon is a Class A carcinogen that, according to scientific studies, cancause harmful affects on human lung tissue. Like VOCs, radon can bedrawn into buildings from the underlying soil and/or groundwater by thenegative pressures that are associated with the structure and featuresof buildings. Negative pressure can be caused by factors such as:temperature differentials where warm air exits an upper portion of abuilding (induces a stack effect), and wind and exhaust appliances thatcreate additional vacuum. These forces can draw in VOC and/or radongases through cracks, conduit openings and other pathways in slabs,sub-slabs or other flooring features of buildings.

SUMMARY

Various systems and methods for reducing vapor contamination, such asVOCs and/or radon contamination, in buildings and structures aredescribed herein. These system and methods may employ active soildepressurization techniques to prevent VOC's, methane and/or radoncontamination within structures and buildings. In some implementations,this can be accomplished by installing a vapor mitigation system that isconstructed and arranged to prevent VOC's, methane and/or radon vaporfrom entering interior building spaces.

For example, some systems and methods described herein are configured tomaintain a pre-specified pressure differential such as two pascals(0.008″ w.c.) between the interior of the building and the underlyingsoil, crawl space or vapor barrier. This can be accomplished byconfiguring a vacuum controller to monitor one or more differentialpressure sensors for sensing pressure between the interior of thebuilding and the sub slab or floor. Based on the measured pressure, thevacuum controller can control the motor speed, riser pipe (vacuum pipe)gate valve position or HVAC supply to achieve specified pressuredifferentials. Sensor performance ranges can be monitored and adjustedon site or remotely over the Internet (via an Internet Interface).

Some systems and methods described herein are configured to controlexhaust contaminant concentrations so as to not exceed predeterminedquantities as set by State or Federal statute. This can be accomplishedby configuring a vacuum controller to monitor mass airflow andcontaminant sensors. Mass airflow indicates volume over time andcontaminate concentrations, weight per volume such as ug/m3. Thesesensors can provide information to the vacuum controller, which cancalculate the total contaminant exhausted, for example, in pounds perhour. Typically contaminant exhaust is regulated in pounds per year.

In some embodiments, the methods and systems induce a specified numberof air changes per hour in the space between the floor and the soil of abuilding, such as in a building with an crawl space (e.g., inaccessiblecrawl space). Mass airflow sensors or individual riser pipes can provideinformation to calculate airflow volume which when combined with theentered volume of the area being depressurized would yield an airexchange rate. The vacuum controller can be configured to control thespeed of the motor and or valves in riser pipes to ensure predeterminedflow volumes. In cases where there is a high rate of air transferbetween the occupied space and the sub floor, such as when there aremultiple conduit penetrations, the HVAC system could be integrated topressurize the occupied space and contribute to the pressuredifferential and volume of exhausted air. All sensor information can bedata logged, monitored and controlled either on site or over theInternet. The vacuum controller can be further configured to regulatethe motor speed and or valves in individual riser pipes to control thetotal volume of contaminate effluent. This information can be logged andmade available on site over the internet. In some embodiments, motorspeeds and riser valve positions could be adjusted remotely to maximizethe overall efficiency of the system to maximize both in powerconservation and contaminant removal.

In one aspect, a vapor mitigation system, comprises: at least one vacuumpipe constructed and arranged to collect vapors beneath a floor of abuilding and to vent the vapors; a blower coupled to the at least onevacuum pipe, the blower constructed and arranged to create a vacuumunder the floor of the building; and a controller configured todynamically control a level of power supplied to the blower, wherein thecontroller adjusts the level of power supplied to the blower in responseto one or more environmental measurements.

In some embodiments, the one or more environmental measurements areselected from the group consisting of: ambient temperature, buildinginterior temperature, building exterior temperature, building sub-slabor floor temperature, building interior air pressure, building exteriorair pressure, a level of vacuum created in the vacuum pipe, a level ofvacuum created under the floor of the building, contaminant detectionand blower mass air flow.

In some embodiments, the vapor mitigation system further comprises avacuum sensor, wherein the vacuum sensor is constructed and arranged todetermine a level of vacuum created under the floor of the building.

In some embodiments, the controller adjusts the level of power suppliedto the blower in response to the level of vacuum.

In some embodiments, the controller increases the level of powersupplied to the blower when the level of vacuum is less than apredetermined level.

In some embodiments, the controller decreases the level of powersupplied to the blower when the level of vacuum is greater than apredetermined level.

In some embodiments, the predetermined level corresponds to regulatorydischarge standards.

In some embodiments, the controller adjusts the level of power suppliedto the blower so that the vacuum created under the floor of the buildingremains substantially constant.

In some embodiments, the controller is configured to adjust the level ofpower supplied to the blower so that the vacuum created under the floorof the building is maintained at a predetermined level.

In some embodiments, the controller is configured to adjust one or moreparameters of an HVAC system.

In some embodiments, the one or more parameters are selected from thegroup consisting of: HVAC supply air pressure, ratio of building returnair to fresh air input.

In some embodiments, the vapor mitigation system further comprises amonitoring system, wherein the monitoring system is configured totransmit a status of the vapor mitigation system to one or more hostmachines via the Internet.

In some embodiments, the vapor mitigation system further comprises afresh air intake pipe constructed and arranged to allow dilution air toflow into an area beneath the floor of the building.

In some embodiments, the controller is configured to increase a level ofpower supplied to the blower in response to an increase in contaminantconcentration beneath the floor of the building.

In some embodiments, the controller is configured to calculate a volumeof dilution air drawn into the area beneath the floor of the building

In some embodiments, the monitoring system is configured to receivesystem configuration parameters from a host machine via the Internet.

In another aspect, a method of mitigating vapors, comprises: generatingan air flow within a passage so as to create a vacuum beneath a floor ofa building; venting the air flow to an exterior of the building; anddynamically adjusting a level of the air flow in response to one or moreenvironmental measurements.

In some embodiments, the one or more environmental measurements areselected from the group consisting of: ambient temperature, buildinginterior temperature, building exterior temperature, building sub-slabor floor temperature, building interior air pressure, building exteriorair pressure, barometric pressure, a level of vacuum created in thevacuum pipe, a level of vacuum created under the floor of the building,contaminant detection and blower mass air flow.

In some embodiments, the level of air flow is dynamically adjusted sothat the vacuum created beneath the floor of the building remainssubstantially constant.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of embodimentsof the present inventive concepts will be apparent from the moreparticular description of preferred embodiments, as illustrated in theaccompanying drawings in which like reference characters refer to thesame elements throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the preferred embodiments.

FIG. 1 is a block diagram of a vapor mitigation system;

FIG. 2 is a block diagram of a dynamically controlled vapor mitigationsystem in accordance with embodiments of the present inventive concepts;

FIG. 3 is a block diagram of another dynamically controlled vapormitigation system in accordance with other embodiments of the presentinventive concepts;

FIG. 4 is a block diagram of another dynamically controlled vapormitigation system in accordance with other embodiments of the presentinventive concepts;

FIG. 5 is a block diagram of a passive vapor mitigation system inaccordance with other embodiments of the present inventive concepts;

FIG. 6 is a block diagram of a dynamically controlled active vapormitigation system in accordance with embodiments of the presentinventive concepts;

FIG. 7 is a flow diagram illustrating a method of controlling a vapormitigation system in accordance with embodiments of the presentinventive concepts.

DETAILED DESCRIPTION OF EMBODIMENTS

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting of the inventiveconcepts. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including,” when usedherein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various limitations, elements,components, regions, layers and/or sections, these limitations,elements, components, regions, layers and/or sections should not belimited by these terms. These terms are only used to distinguish onelimitation, element, component, region, layer or section from anotherlimitation, element, component, region, layer or section. Thus, a firstlimitation, element, component, region, layer or section discussed belowcould be termed a second limitation, element, component, region, layeror section without departing from the teachings of the presentapplication.

It will be further understood that when an element is referred to asbeing “on” or “connected” or “coupled” to another element, it can bedirectly on or above, or connected or coupled to, the other element orintervening elements can be present. In contrast, when an element isreferred to as being “directly on” or “directly connected” or “directlycoupled” to another element, there are no intervening elements present.Other words used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). When an elementis referred to herein as being “over” another element, it can be over orunder the other element, and either directly coupled to the otherelement, or intervening elements may be present, or the elements may bespaced apart by a void or gap.

FIG. 1 is a block diagram of a vapor mitigation system. A vapormitigation system 10 can be installed and/or provided in a building orstructure 20, and may comprise one or more vacuum pipes 11 and aconstant power/speed blower 12. In this exemplary embodiment, the vapormitigation system 10 is arranged to create a vacuum under the floor orbuilding slab 20 s (or vapor barrier) of the building 20 so as tocollect VOC and/or radon vapors. The vapor mitigation system 10 isfurther arranged to vent an exhaust airflow of VOC's, methane and/orradon vapors above the building roof 20 r.

In the vapor mitigation system 10 shown in FIG. 1, one or more vacuumpipes 11 are arranged to collect vapors beneath the floor or buildingslab 20 s of the building 20. A first opening of the vacuum pipe 11 ispositioned beneath the floor or building slab 20 s and a second openingof the vacuum pipe 11 is coupled to a constant power/speed blower 12 soas to create a vacuum (negative pressure) under the floor or buildingslab 20 s of the building 20.

The vapor mitigation system 10 is configured based on collectedmeasurements 17 (e.g., ambient pressure and temperature of the buildinginterior 20 i, vacuum pipe pressure (vacuum level) and building slabvacuum pressures) at various levels of applied vacuum. That is, aninstaller makes a series of manual adjustments (i.e., air flowrestriction) to the system 10 in response to collected measurements. Forexample, in response to an initial collection of measurements, the levelof applied vacuum pressure by the system 10 can be manually adjusted byopening or closing a gate valve 13, which is shown coupled between thefirst and second ends of the vacuum pipe 11. However, the restriction ofair flow created by the closing of the gate valve 13 introduces energyinefficiencies into the system 10, since the blower 12 is operated at aconstant speed/power. Accordingly, more power may be consumed by theconstant power/speed blower 12 than is required to achieve the desiredvacuum level.

Further, the vapor mitigation system 10 is configured to apply anoverwhelming vacuum pressure underneath the floor or building slab 20 sof the building 20 so as to compensate for various changes in buildingand environmental conditions. For example, pressures within the buildinginterior 20 i change due to wind loading and stack effect of appliances,such as HVAC systems. Accordingly, the vapor mitigation system 10 isconfigured to apply an overwhelming vacuum underneath the floor orbuilding slab 20 s of the building 20 so that a minimum vacuum level isapplied irrespective of changing building or environmental conditions.

Furthermore, changing environmental conditions, such as sub-slabmoisture content and/or barometric fluctuations, can result in anexcessive amount of vacuum being applied by the system 10. This canlikewise introduce energy inefficiencies, and may require further designand calibration of the system 10 (which can introduce other economicinefficiencies).

The vapor mitigation system 10 may further comprise an alarm panel 15and a vacuum switch 14, which is configured to detect the presence of anapplied vacuum. In response to the binary detection of an appliedvacuum, the alarm panel 15 can issue an on-site alarm if the vacuumpressure falls below a predetermined level.

FIG. 2 is a block diagram of a dynamically controlled vapor mitigationsystem in accordance with embodiments of the present inventive concepts.A dynamically controlled vapor mitigation system 100 can be installedand/or provided in a building or structure 20, and may comprise one ormore riser pipes or vacuum pipes 110, a vacuum controller 150 and avariable power/speed blower 120. The vapor mitigation system 100 mayfurther include any of the above features or elements of the vapormitigation system 10 described above with reference to FIG. 1.

The vapor mitigation system 100 is constructed and arranged to create avacuum under a floor or building slab or vapor barrier 20 s of abuilding 20 so as to collect VOCs, methane and/or radon vapors, and maybe further be arranged to vent an exhaust airflow of VOCs, methaneand/or radon vapors above the building roof 20 r. In the dynamicallycontrolled vapor mitigation system 100 shown in FIG. 2, one or morevacuum pipes 110 are arranged to collect vapors beneath the floor orbuilding slab 20 s of the building 20. In some embodiments, a firstopening of the vacuum pipe 110 is be positioned beneath the floor orbuilding slab 20 s and a second opening of the vacuum pipe 110 iscoupled to a variable power/speed blower 120 so as to create a vacuumunder the floor or building slab 20 a of the building 20. Although notshown, a plurality of vacuum pipes 110 may be positioned to create thevacuum under the floor or building slab 20 s of the building 20. Forexample, a plurality of vacuum pipes 110 and/or a single vacuum piperhaving a plurality of vacuum pipe inlets 110 i may be positioned tocreate vacuum zones (a first vacuum zone is shown in FIG. 2). In thismanner, the dynamically controlled vapor mitigation system 100 can bearranged and/or configured to vent an exhaust airflow of VOC, methaneand/or radon vapors above the building roof 20 r.

The vacuum controller 150 of the system 100 can include a microprocessoror other type of processing system that configured to control and/oradjust the level of vacuum applied under the floor or building slab 20 sof the building 20 in response to building and/or environmentalmeasurements. These measurements may include, for example, ambientand/or interior temperatures (ambient temperature sensor 160 a),building interior air pressure (ambient temperature sensor 160 b),building exterior air pressure, such as barometric pressure (ambienttemperature sensor 160 b), building sub-slab or vapor pressure, or floorair pressure (zone vacuum sensor 160 c), contaminant detection(contaminant sensor 160 d), vacuum pipe pressure (vacuum/pressure sensor132) and/or blower mass air flow (mass air flow sensor 140).

In some embodiments, the system 100 may be configured to reduce thespeed of the blower 120 in response to a blower mass air flowmeasurement. For example, the blower mass air flow measurement mayindicate a large volume of air that may exceed the blower's 120 motorfactor. In response to the blower mass air flow measurement, the vacuumcontroller 150 may decrease the power/speed of the blower 120 so as notto exceed the blower's 120 motor factor. In addition, the blower massair flow measurement may indicate a volume of contaminate removed fromthe sub slab or floor environment, which can trigger the vacuumcontroller 150 to increase or decrease the applied vacuum.

The vacuum controller 150 may be configured to vary the power applied tothe blower 120 (so as to adjust the blower fan speed and applied vacuum)and/or to adjust the opening or closing of an electronically controlledgate valve 130 (optional) in response to the building and/orenvironmental measurements. For example, the vacuum controller 150 maybe configured to regulate the air flow within the one or more vacuumpipes 110 (e.g., which can be sensed by the mass air flow sensor 140) sothat various sub slab vacuum fields can be balanced and/or to apportionsub slab vacuum pressure to specific areas that have higher contaminantconcentrations or Lower Explosive Limit (LEL), oxygen content or othercontaminant extraction goals. A plurality of electronically controlledgate valves 130 may be provided so as to control applied vacuumpressures in embodiments having multiple air flow inlets 110 i.

The vacuum controller 150 may be configured to vary the power applied tothe blower 120 and/or to adjust the opening or closing of anelectronically controlled gate valve 130 (optional) to control an amountof contaminants discharged into the atmosphere. For example, some Stateshave permitable discharge standards that relate to annual gross poundsof contaminant discharged to the atmosphere. By measuring and collectingthe contaminate concentrations and the discharge velocity ofcontaminants, the vacuum controller 150 may be configured to calculate atotal contaminate discharge. Based on the total contaminate discharge,the vacuum controller 150 can reduce the power/speed of the blower 120so that the amount of contaminant discharged into the atmosphere isreduced. In this manner, the system can be configured to reducecontaminant discharged so as not to exceed regulatory dischargestandards.

The vacuum controller 150 can determine and control an optimum vacuumlevel to be applied under the floor or building slab 20 s. Accordingly,energy efficiencies can be increased by monitoring the building and/orenvironmental measurements, and reducing the power/speed of the blower120 when the vacuum applied under the floor or building slab 20 sexceeds operating requirements. In addition, the controller 150 canincrease the power/speed of the blower 120 if a high level ofcontaminants are detected within the building interior 20 i.

The building and/or environmental measurements can be acquired via oneor more sensors 140, 160 a-d electronically coupled to the controller120. For example, the sensors 140, 160 a-d may be electrically coupledto the controller 120 via wires or cables (e.g., direct or indirectwired connections, network connections, ect . . . ), or, additionally oralternatively, the sensors 140, 160 a-c may be wirelessly coupled to thecontroller 120.

In some embodiments, the dynamically controlled vapor mitigation system100 may include one or more of the following sensors: a mass air flowsensor 140, an ambient pressure sensor(s) 160 a (interior and/orexterior building pressure sensors), an ambient temperature sensor(s)160 b (interior and/or exterior building pressure sensors), an inlinezone vacuum sensor 160 c and a contaminant sensor 160 d. The mass airflow sensor 140 may be coupled to the one or more vacuum pipes 110,between an airflow inlet 110 i and an airflow outlet 110 o. The ambienttemperature sensor(s) 160 b and ambient pressure sensor(s) 160 a may beprovide within the building interior 20 i, exterior to the building, andor beneath the building floor or slab 20 s. The data from the pressuresensors 160 a processed by the vacuum controller 150 to determineinterior/exterior/sub floor differential pressures. The contaminantsensor 160 d may be provided within the interior of the building so thata level of chemical contamination can be monitored; however,alternatively or additionally, the contaminant sensor 160 d may becoupled to or provided within the vacuum pipes or beneath the floor slab110 so that contaminant content drawn from specific vacuum zones can bemeasured.

During operation of the system 100, the vacuum controller 150 may beconfigured to provide a blower motor power/speed command to a variablefrequency motor drive controller 125. In response to the blower motorpower/speed command, the variable frequency motor drive controller 125adjusts a power output supplied to the blower 120, which in turn affectsthe speed of the blower 120 and the level of applied vacuum. Inaddition, the vacuum controller 150 may provide a gate valve command tothe electronically controlled gate valve 130 (if used). In this manner,the vacuum controller 150 can be configured to maintain a predeterminedand/or constant sub floor vacuum level when other conditions, such asenvironmental and/or building conditions, change. For example, changesin soil moisture, stack effect, wind loading and seasonal atmosphericconditions my affect the floor vacuum level or contaminantconcentrations. Accordingly, the system 100 can be more economical tooperate since only the required level of vacuum is created.

Referring to FIGS. 2 and 3, the dynamically controlled vapor mitigationsystem 100 may further include a monitoring system 170, which cangenerate, transmit and/or provide system alerts and faults. Additionallyor alternatively, the monitoring system 170 can provide onsite and/oroffsite network access to the system 100 so that workers and/or othersystem maintenance professionals can inspect and/or adjust operatingparameters of the system 100. For example, the monitoring system 170 caninclude a first and second web interfaces 172, 174 that can be accessedvia a local area network and/or the Internet. The first web interface172 provides access to system control parameters, and the second webinterface 174 provides access to system monitoring and alarm indicatorsand signals.

The monitoring system 170 can also be configured to collect data, suchas system status data and/or environmental data so that systemmaintenance can be scheduled before a complete failure of the systemoccurs, thus reducing maintenance costs and minimizing building occupantcontaminant exposure. This data, along with system alerts and/or faults,can be sent via the Internet to a host system that can collect the dataand issue alarms or status updates electronically. Additionally oralternatively, the monitoring system 170 of the vacuum controller 150can transmit alerts via common data services, such as email or textmessaging. Accordingly, unattended buildings can be monitored at a lowcost, since onsite checkups may be reduced and/or eliminated.

The system 100 may further comprise backup settings or backup settingcircuitry 126 that configure the operation of the blower 120 in thatcase of a vacuum controller fault. For example, if the vacuum controller150 is unable to determine an optimum vacuum level or the backup settingcircuitry identifies a fault with the vacuum controller 150, the backupsetting circuitry 126 can configure the blower 120 to operate in apredetermined state. The predetermined state may correspond to a vapormitigation system configuration based on collected measurements (e.g.,such as the system configuration described with reference to FIG. 1).

FIG. 4 is a block diagram of another dynamically controlled vapormitigation system. Further to the dynamically controlled vapormitigation systems 100 shown in FIGS. 2 and 3, the vacuum controller 150may be further configured to control the floor or slab 20 s vacuumpressure by interfacing with the building HVAC system 180. In someimplementations, the controller 150 may be configured to control variousparameters of the building HVAC system 180. For example, the controller150 my command the building HVAC system 180 to introduce a greateramount of fresh air into the interior of the building 20 i so as toreduce contaminant concentrations detected by the contaminant sensor 160d.

In some embodiments, the vacuum controller 150 may be configured tocontrol one or more parameters of the building HVAC system 180 so as toadjust an interior building pressure and/or the amount of fresh airsupplied to the building interior 20 i. For example, the convectiveforces of the HVAC system 180 may create negative pressures within thebuilding interior 20 i, which can draw VOC's, methane and/or radonvapors into the building interior 20 i. In response to the convectiveforces, the vacuum controller 150 may be configured to counterbalancethe affects of the convective forces by mechanically pressurizing thebuilding interior 20 i with excess exterior air (e.g., fresh air input).Furthermore, the exterior air drawn into the building interior 20 ithrough the HVAC system 180 generally has a lower concentration ofcontaminants. Accordingly, the vacuum control 150 may be configured todilute the air within the building interior 20 i to further lower indoorcontaminate concentrations.

The vapor mitigation system 100 may further include any of the abovefeatures or elements of the vapor mitigation systems 10, 100 describedabove.

FIG. 5 is a block diagram of a passive vapor mitigation system. A vapormitigation system 200 can be installed as part of a new constructionbuilding 20, or installed as part of an existing building 20. The vapormitigation system 200 includes one or more vacuum pipes 110 forcollecting and venting soil vapors (VOC vapors, radon vapors and/orother vapors). For example, in the present exemplary embodiment, acollection box 111 having a network of gas conveyance pipes 112 is showncoupled to the vacuum pipe 110. The network of gas conveyance pipes 112collects soil vapors from beneath the building floor or slab 20 s, andfunnels the soil vapors to the collection box 111 where the soil vaporsare vented to an exterior of the building by the vacuum pipe 110. Thevapor mitigation system 200 is constructed and arranged to createnatural convection under the floor, vapor barrier or slab 20 s of thebuilding 20 so as to collect and vent the soil vapors without the use ofa transport device, such as a blower or fan.

The vapor mitigation system 200 can be configured to monitor theperformance of new construction passive systems or existing constructionpassive systems, which rely on convective airflow that is induced byweather and building features. The operation of these systems 200 isdependent upon the construction features and weather. Constructionfeatures of the building can include such features as: angularityheight, HVAC system. These features can affect the convective flow ofair and induce pressure differentials between the interior of thebuilding and the underlying soil or sub floor. The weather,interior/exterior pressure differentials such as forces applied on abuilding by wind, and changes in the barometer can cause fresh dilutionair to move down the riser pipe or vacuum pipe 110 and into the sub slabsoil environment as well as create convective venting of the sub slab.Monitoring the condition of the systems 200 enables consultants tomeasure the passive effectiveness of the systems 200 as well as developa data base to support continued passive venting or provide cause tochange the system to active by installing a blower.

The vapor mitigation system 200 includes a floor system 20 fs forcollecting the gaseous vapors from beneath the building floor or slab 20s. In one embodiment, the floor system 20 fs includes a bed of crushedstone 190 that surrounds the network of conveyance pipes 112 and/or thecollection box 111. The floor system 20 fs can also include a crawlspace and/or a vapor barrier 195 to prevent the soil vapors fromentering the building interior 20 i. In another embodiment, the bed ofcrushed stone 190 is replaced with an aerated floor system 195, such asCupolex®. The aerated floor system 195 can include a grid ofinterconnected plastic arch forms that are applied over the soil priorto the pouring of concrete, which creates hollow spaces beneath the slab20 s after the concrete is poured and cured. The network of conveyancepipes 112 collect the soil vapors beneath the building floor or slab 20s so that the soil vapors can be passively vented to an exterior of thebuilding 20.

In situations where it is unclear what design (crushed stone or aeratedfloor system) is the most efficient and effective solution from anenvironmental abatement, energy efficiency and financial effectivenesspoint of view, a data collection system 240 and a series of monitoringsensors 210, 215, 220, 225, 230, 250, 253, 255 can be installed. Bycomparing data from systems 200 that utilize a bed of crushed stone 190and systems 200 that utilize an aerated floor system 195, buildingengineers and consultants can determine which design (crushed stone oraerated floor system) is the most efficient and effective solution.

The data collection system 240 is connected to a plurality of monitoringsensors, and is configured to collect data during operation of thesystem 200. For example, the data collection system 240 can be connectedto a mass airflow sensor 210 for determining a mass flow rate anddirection of air exiting/entering the vacuum pipe 110, an air humiditysensor 215 for determining the humidity of air exiting/entering thevacuum pipe 110, an air temperature sensor 220 for determining thetemperature of air exiting/entering the vacuum pipe 110, inline pressuredifferential sensors for determining directional convective flowpressure 225, and a contaminate sensor 230 for determining a type andconcentration of contaminant within the air exiting/entering the vacuumpipe 110. The data collection system 240 can also be connected to aninterior temperature sensor 250 for sensing the ambient temperaturewithin the building interior 20 i, and an interior pressure sensor 255for sensing the pressure within the building interior 20 i. The datacollection system 240 can be connected to soil gas sensors 253 forsensing VOC's, methane gas and/or radon gas.

The data collected and recorded by the data collection system 240 can beaccessed by building engineers and consultants via a web interface172/174 for determining various operating conditions of the vapormitigation system 200 over a period. For example, directional air flowdata collected from the mass airflow sensor 210 can indicate whether thesystem 200 is venting soil gases or recharging the soil (sub slab) withoutside air.

Changes in barometric pressure, temperature, airflow around a buildingand convective variation are all variables that contribute to theeffectiveness of passive venting. By monitoring contaminantconcentrations and other system parameters, designers, buildingengineers and consultants can quantify the effectiveness of thesesystems and determine which designs are best suited for the contaminatesoil conditions and features of a particular building or structure. Thedata collection and processing system 240 allows the designers, buildingengineers and consultants with data that can be used to evaluate theeffectiveness of various passive soil gas vent designs.

FIG. 6 is a block diagram of a dynamically controlled vapor mitigationsystem. A vapor mitigation system 200 can be installed as part of a newconstruction building 20, or installed as part of an existing building20. In some embodiments, the vapor mitigation system 200 can havesufficient passive convection (natural convention) to effectively ventthe sub slab. However, in other embodiments, changing environmentalfactors can prevent the vapor mitigation system 200 from venting the subslab in a passive mode alone. To properly vent the sub slab, the vapormitigation system 200 can be further configured with active ventingelements. For example, the vapor mitigation system 200 can include ablower 120, a variable frequency motor drive 125 and a vacuum controller150. The vacuum controller 150 can be configured to operate the blower120 in response to data received from the data collection and processingsystem 240 and the sensors 210, 215, 220, 225, 230, 253 coupled to thevacuum pipe 110 and/or the fresh air intake. For example, if directionalair flow data collected from the mass airflow sensor 210 or the pressuredifferential sensor 225 indicates that the system 200 is recharging thesub slab with outside air, the vacuum controller 240 can activate theblower 120 (thereby applying a vacuum pressure to the sub slab) toreturn the system 200 to a venting state. While the vacuum controller150 and data collection and processing system 240 are shown as separateblocks, these elements can be implemented by the same processor orcontroller element. The vapor mitigation system 200 can include any ofthe above features or elements of the active vapor mitigation systems100 shown and described in connected with FIGS. 1-4.

In some passive and active embodiments, the system 200 includes a freshair intake that can be positioned, for example, in the side wall 20 swof the building 20. The fresh air intake 114 includes piping, and isconstructed and arranged such that an inlet of the fresh air intakepiping is positioned at an exterior of the building and an outlet of thefresh air intake piping is positioned beneath the building floor or slab20 s. The fresh air intake 114 provides for the conveyance of outsidedilution air to the sub slab or floor soil environment of the building20. The fresh air intake 114 can be provided in systems 200, forexample, when it is beneficial to mix fresh air with the soil gases thatare seeping out from the vadose zone of the soil environment beneath thebuilding 20 for the purpose of lowering the potential for combustion orexplosion of the soil gases. The ambient dilution air provided by thefresh air intake 114 can also be used to lower volumetric contaminantconcentrations beneath the building floor or slab 20 s. In someembodiments, the vacuum pipes 110 are located in the center of thebuilding 20 or on a sidewall that is opposite the inlet of the fresh airintake 114 so as to attain maximum dilution benefit from theintroduction of fresh air.

The vacuum controller 150 of the system 100 is configured to controland/or adjust the level of vacuum applied under the floor or buildingslab 20 s of the building 20 in response to building and/orenvironmental measurements. These measurements can include, for example,ambient temperatures, interior vacuum pipe temperatures, buildinginterior air pressure, building exterior air pressure, building sub slabor floor air pressure, contaminant detection, blower mass air flow,direction of airflow and/or in riser vacuum measurements. In someembodiments, the system 200 can be configured to operate in a passivemode (blower off) when there is sufficient passive convection (naturalconvention) to effectively vent the sub slab, and can be configured tooperate in the active mode (blower on) when there is insufficientpassive convection.

As described above in connection with the active vapor mitigationsystems of FIGS. 2-4, the vacuum controller 150 may be configured tovary the power applied to the blower 120 (so as to adjust the blower fanspeed and applied vacuum) and/or to adjust the opening or closing of anelectronically controlled gate valve 130 (not shown) in response to thebuilding and/or environmental measurements.

For example, when the sub slab soil gas sensor 253 nearest the vacuumpipe 110 or near the fresh air intake measure contaminant concentrationsthat exceed predetermined sub slab concentrations, the data collectionsystem 240 and/or the vacuum controller can activate the blower 120 orincrease the speed of the blower 120 to exhaust the contaminants andlower the contaminant concentration. In some embodiments, the sub slabvacuum induced by the blower 120 opens a one way valve 280 of the freshair intake 114, which permits fresh air to be drawn through the subslab. The data collection system 240 can collect and record data fromsensors 210, 215, 220, 225, 230 of the fresh air intake 114, such asbarometric pressure, mass airflow, vacuum pipe pressure differentials,air temperature, air humidity and contaminant concentration. Contaminantconcentrations near the fresh air intake may reduce quickly in responseto the vacuum induced by the blower 120, while contaminantconcentrations near the vacuum pipe 110 inlet may reduce at a slowerrate. When contaminant sensors determine that contaminant concentrationsnear the vacuum pipe 110 inlet and/or in the vacuum pipe 100 itself arereduced to a predetermined level, such as Lower Explosive Limit (LEL),the motor speed of the blower 120 is reduced or the blower 120 is turnedoff by the system 200 for the purpose of conserving energy.

In this manner, the vacuum controller 150 can determine and control theon/off position or create an optimum vacuum level to be applied underthe floor or building slab 20 s. Accordingly, energy inefficiencies canbe reduced by monitoring the building and/or environmental measurements,and reducing the power/speed of the blower 120 when the vacuum appliedunder the floor or building slab 20 s exceeds operating requirements. Inaddition, the controller 150 can increase the power/speed of the blower120 if a higher level of contaminants are detected within the buildinginterior 20 i.

The methods and processes disclosed herein can be implemented by theabove systems and devices, or equivalent systems and devices, executinga unique set of instructions stored or embodied in computer accessiblemedia. As will be appreciated by those skilled in the art, a unique setof instructions can be implemented or embodied as executable code, suchas, software, firmware, machine code or a combination thereof. As such,the unique set of instructions stored or embodied in computer accessiblemedia transforms the above systems and devices into particular, specialpurpose systems and devices that can operate, for example, according tothe following exemplary flow diagrams. In some embodiments, unique setsof instructions correspond to the methods and processes disclosed FIG. 7and described below in further detail.

FIG. 7 is a flow diagram illustrating a method of controlling a vapormitigation system. The flow diagram illustrates a method 300 ofcontrolling a vapor mitigation system 100, 200. At step 310 thecontroller (vacuum controller or processing system) compares presetpressure zone set points to measurements captured by the sub slabpressure sensors in each of the zones being controlled. The outputs atstep 310 are the pressure zone error signals. At step 320 the zonepressure error signals are modified by the compensated ambient pressurelevel, which is a composite signal of the ambient pressure and ambienttemperature which is generated at step 315. The outputs of step 320 arethe airflow commands. At step 330 the magnitude of the airflow commandsare used to generate gate valve position commands and the fan speedcommand signals. The fan speed signals are used to control the variablespeed motor drive that controls the fan speed as shown in FIGS. 2-4 and6. At step 340, the gate valve position commands are modified based onthe output of the mass airflow sensor 345. The gate valves arepositioned accordingly to the commands generated from step 340.

While the present inventive concepts have been particularly shown anddescribed above with reference to exemplary embodiments thereof, it willbe understood by those of ordinary skill in the art, that variouschanges in form and detail can be made without departing from the spiritand scope of the present inventive concepts described and defined by thefollowing claims.

What is claimed is:
 1. A vapor mitigation system comprising: at leastone vacuum pipe configured to collect vapors from a sub slab environmentbeneath a building and to vent the vapors; a contaminate sensorconfigured to determine a concentration of a contaminant within thevapors collected within the at least one vacuum pipe; a blower coupledto the at least one vacuum pipe, the blower configured to create avacuum in the sub slab environment relative to ambient pressure withinthe building; a fresh air inlet pipe that provides outside air to thesub slab environment; a valve that dynamically limits a flow of outsideair to the sub slab environment through the fresh air inlet pipe; and acontroller in communication with the blower, the contaminant sensor, andthe valve, the controller being configured to dynamically control thevalve to limit the flow of outside dilution air to the sub slabenvironment based on the concentration of the contaminant in the vacuumpipe, wherein the dynamic control of the valve comprises, responsive tothe contaminant sensor determining that the concentration of thecontaminant within the vacuum pipe exceeds a predetermined thresholdlevel, providing a signal to temporarily open the valve to permit theflow of outside dilution air to the sub slab environment.
 2. The vapormitigation system of claim 1 further comprising a vacuum sensorconfigured to determine the level of vacuum created in the sub slabenvironment.
 3. The vapor mitigation system of claim 2, wherein thecontroller decreases the speed of the blower when the level of vacuum isgreater than a predetermined level.
 4. The vapor mitigation system ofclaim 1, wherein the controller is further configured to dynamicallycontrol a level of power supplied to the blower, wherein the controlleradjusts the level of power supplied to the blower in response to one ormore environmental measurements.
 5. The vapor mitigation system of claim4, wherein the controller adjusts the speed of the blower so that thelevel of vacuum created in the sub slab environment remainssubstantially constant.
 6. The vapor mitigation system of claim 1,wherein the controller is configured to adjust the speed of the blowerso that the level of vacuum created in the sub slab environment ismaintained at a predetermined level.
 7. The vapor mitigation system ofclaim 1, wherein the controller is configured to transmit a status ofthe vapor mitigation system to, and/or to receive system configurationparameters from, one or more host machines via the Internet.
 8. Thevapor mitigation system of claim 1, wherein the valve comprises a oneway valve.
 9. The vapor mitigation system of claim 1 further comprisinga monitoring system configured to provide access to operating parametersof the vapor mitigation system.
 10. The vapor mitigation system of claim9, wherein the monitoring system includes a web interface for adjustingthe operating parameters of the vapor mitigation system.
 11. The vapormitigation system of claim 9, wherein the monitoring system isconfigured to collect system status data.
 12. The vapor mitigationsystem of claim 11, wherein the monitoring system is configured totransmit the system status data to a host machine via the Internet. 13.The vapor mitigation system of claim 1, further comprising a sub slabsoil gas sensor configured to determine a concentration of thecontaminant within the sub slab environment.
 14. The vapor mitigationsystem of claim 13, wherein the controller is configured to dynamicallycontrol the valve to limit the flow of outside dilution air to the subslab environment based on the concentration of the contaminant in thesub slab environment.
 15. The vapor mitigation system of claim 1 whereinat least one of the at least one vacuum pipes is located in a centralregion of the building and the fresh air inlet pipe enters the buildingthrough a side wall of the building.
 16. A vapor mitigation systemcomprising: a blower coupled to at least one vacuum pipe, the blowerconfigured to extract vapor from a sub slab environment beneath abuilding and to vent the vapors through the at least one vacuum pipe; amass air flow sensor coupled to the at least one vacuum pipe, the massair flow sensor configured to measure a level of mass flowrate of vaporextracted from the sub slab environment; a contaminant sensor coupled tothe at least one vacuum pipe, the contaminant sensor configured tomeasure a level of contaminant in the vapor extracted from the sub slabenvironment; a valve that dynamically limits a flow of outside air tothe sub slab environment through the fresh air inlet pipe; and acontroller in communication with the blower, the mass air flow sensor,the contaminant sensor, and the valve, the controller being configuredto: i) calculate an amount of contaminant extracted from the sub slabenvironment; and ii) dynamically control the valve to limit the flow ofoutside dilution air to the sub slab environment based on theconcentration of the contaminant in the vapor extracted from the subslab environment, wherein the dynamic control of the valve comprises,responsive to the contaminant sensor determining that the concentrationof the contaminant the vapor extracted from the sub slab environmentexceeds a predetermined threshold level, providing a signal totemporarily open the valve to permit the flow of outside dilution air tothe sub slab environment.
 17. The vapor mitigation system of claim 16,wherein the controller is further configured to adjust the speed of theblower in response to the concentration of the contaminant extractedfrom the sub slab environment.
 18. The vapor mitigation system of claim16, wherein the controller is further configured to adjust the speed ofthe blower so that the amount of contaminant exhausted away from thebuilding does not exceed a predetermined amount of contaminant.
 19. Thevapor mitigation system of claim 16, wherein the valve is a one wayvalve.
 20. A vapor mitigation system, comprising: a blower coupled to atleast one vacuum pipe, the blower configured to extract vapor from a subslab environment beneath a building; a mass air flow sensor coupled tothe at least one vacuum pipe, the mass air flow sensor configured tomeasure a mass flowrate of vapor extracted from the sub slabenvironment; a contaminant sensor coupled to the at least one vacuumpipe, the contaminant sensor configured to measure a level ofcontaminant in the vapor extracted from the sub slab environment; afresh air inlet pipe that provides outside air to the sub slabenvironment a valve that dynamically limits a flow of outside air to thesub slab environment through the fresh air inlet pipe; and a controllerin communication with the blower, the mass air flow sensor, thecontaminant sensor, and the valve, the controller being configured to:i) adjust a speed of the blower so that the mass flowrate of vaporextracted from the sub slab environment remains substantially constant;and ii) dynamically control the valve to limit the flow of outsidedilution air to the sub slab environment based on the concentration ofthe contaminant in the vapor extracted from the sub slab environment,wherein the dynamic control of the valve comprises, responsive to thecontaminant sensor determining that the concentration of the contaminantthe vapor extracted from the sub slab environment exceeds apredetermined threshold level, providing a signal to temporarily openthe valve to permit the flow of outside dilution air to the sub slabenvironment.